SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f329af858162d25fc6e8f58657e0c291942c57fc024abfb75497f22a3986459d' 
  AND token = 'jGQTnxCFy3xcu8XJhtmg4t17MjqCzWOklwY1fZEdFu4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}